Sweeper

Like others have said, it happens when applying throttle from a steady cruise 2000-2500 rpm, 2nd gear. It is just 1 ping then gone. I've tried to duplicate it by slighty lugging the engine, and over throttling it. Nothing.
It only happens with that one condition. really weird.

I was thinking maybe the alchohol in todays gas, retaining moisture, and causing a really fast burn.

Zba

Has anyone verified that it is actually a detonation issue and not something else? A quick jab of the throttle building oil pressure in the cam adjuster possibly? I have worked for Porsche for six years, first in Massachusetts, now in Colorado and not once have I experienced detonation while on a road test, NOR have i ever had any customers come in with that concern.
Chad

RollingArt

The sound is not valve clatter. The pinging noise is the sound of the combustion being propagated by a sudden shock wave of combustion and not a healthy thermal flame front.

I've heard a little pinging from my C2S. I often mix in some 100 octane Sunoco with my 91 oct fuel and the ping stops.

The ping is very minor and not enough to do any damage. Most owners probably don't even notice it. If the radio is on you won't hear it. If everyone turned off their radios and really listened for it during low RPM work, I think most would find that their car is also capable of an occasional "ping".



Phil

Mike in CA

Thanks for the clarification. I'd always thought that the increase in cylinder pressure caused by combustion at the wrong point in the cycle could cause rattle in the valve train, because the valves were not in proper position. In any event, I'm pretty **** about unusual noises in my cars and I can't recall the last time I heard pinging. And I rarely listen to the radio while driving.

Fahrer

It is good to have advanced ignition timing to improve effeciency but it appears that computer is a little slow to retard the timing when there is a demand for power.

Da Hapa

My 2008 997S will ping from time to time at low load and low RPM's. My dealer and the local Porsche rep. both investigated it. They both told me it's "normal" and due to 91 octane gas in CA as these cars are tuned to run on 93.

In order for the knock sensors to work... there has to be knock first. At least that's what the Porsche people told me.

It absolutely stops if I blend a few gallons of 100 octane into a full tank but that's not cheap to do.

I'm frankly a little disappointed but not surprised that CA is screwing me again

runner1021

Are you experiencing a "ping", or what feels like a slight misfire? My 997.2 has exhibited this slight hesitation @ approx. 2700 rpm since new. In discussing this with several technicians, they all appear to believe it is simply the variocam switching from low to high speed mode, and of course the obligatory "they all do that."

jay997

A misfire is one thing, a ping is something else. The pings I experience in my 997.1 C2S has NO hesitation
just your run of the mill ping or click, but just occasionally. When I drive it harder or shift at higher rpms it doesnt occur. It does seem to occur between 2500-2700 rpms shifts. I too chalk it off as 91 octane, as its the highest octane available in california. I know racing fuel is an answer, or a few gallons of it to bump up the octane, but again not a solution.

jes999

I added 2 gallons of 100 Octane at the last fill-up and it seems to have solved the issue, but @ $8/gallon, it is a steep price to pay for living in a state that mandates 91 Octane fuel!

John Velasco

It is more how you take off and less about the octane rating.

Da Hapa

Not according to Porsche.

Bigwave

Has anyone tried an octane boost such as NOS etc...

Edgy01

What you are experiencing is engine knock due to the lower fuel octane in California. While in Europe with German Super Bleifrei (leadfree) fuel I never experienced that. Got it routinely in California during the right conditions. It takes a little work on the foot to learn how to avoid creating that condition (to avoid it) due to the octane shortcomings. When I have added an octane supplement to the car in California it immediately went away. (I used to run ST104 in my Turbo years ago to get the octane up high enough to avoid engine damage under boost--worked well). I'm not sure that that stuff is good for long term use with these engines of today. Perhaps blending in racing fuel occasionally when you need it can fix that.

Macster

Knock sensors are tuned to detect vibrations arising from pre-knock/detonation conditions, vibrations that preceed knock/detonation. If the sensors were instead tuned to only signal upon detection of vibrations arising from knock/detonation it would be too late for the engine.

I've covered a lot of miles in my Porsches running the engines on CA 91 octane gasoline. Granted it is crappy gasoline but I've never encountered pinging from my Porsche engines except from the occasional mistep with the clutch and throttle that sees me "launch" the car with too little rpms. There's a brief flurry of pinging then. But normal launches and for the Boxster this requires barely rpms above 1100 and a smooth release of the clutch pedal with then more throttle once the clutch fully released and the car moving off does not produce any pinging.

The Turbo requires a bit more attention cause the clutch's a bit more sensitive and lighter and has less feel but again no pinging.

And neither car pings at any other time. Now I do avoid high gear heavy load running. No full throttle acceleration runs in 6th gear from under 2K rpms and in fact no full throttle acceleration in 6th gear under 3K rpms.

Lower gears can see high acceleration the lower the gear the more torque demand I make of the engine.

Now other cars it is different. My 96 Mustang GT with the 4.6l SOHC engine and just around 9:1 compression ratio pinged all the time and even with premium gas even though the owners manual specified to use 87 octane.

I attributed this to simply poor combustion chamber design.

Sincerely,

Macster.

jes999

Service advisor at the dealer recently recommedned using the Techron fuel injector cleaner and staying away from cheap fuel (Costco, Sams Club, etc.) at all cost. 1 bottle of Techron Pro-Gard Injector cCeaner and two tank fulls of "good gas" and the pings are completely gone! I generally did not use the cheap gas (maybe 1 out of every 4 or 5 tanks) but the previous owner used it exclusively based on the receipts that came with the car.